We have talked about the immigration of Muslims into France and Holland and Turks into Germany. Europe needs immigrant labor to provide cheap labor. The problem is these peoples do not assimilate into European culture, creating friction and a future time bomb. One of the reasons for the increased need for immigrant labor is the declining population. An article in The Independent covers this fact. Here is a quote:

"...the fertility rate in Europe is "insufficient to replace the population" and adds: "Never in history has there been economic growth without population growth."

More controversially, the green paper also concludes that "ever larger migrant flows may be needed to meet the need for labour and safeguard Europe's prosperity".